Hybrid power system including an engine and a fuel cell module

ABSTRACT

A mixture of a fuel gas obtained by vaporizing hydrocarbon and air is burned in an engine  11  to generate mechanical power. The fuel gas obtained by reforming the hydrocarbon is supplied to a fuel electrode layer of a fuel cell module  13  in which plural electric power generating cells each including a solid electrolyte layer, and a fuel electrode layer and an air electrode layer disposed on both sides thereof are laminated, and the air or oxygen is supplied to the air electrode layer, so that the fuel cell module  13  is constructed to be capable of generating electric power at 930° C. or lower. One of or both of mechanical power generated by the engine  11  and electric power generated by the fuel cell module  13  are outputted. As a raw material of the fuel gas supplied to the fuel cell module, gasoline, light oil or the like which can be supplied in a normal gasoline station can be used.

TECHNICAL FIELD

The present invention relates to a hybrid power system using a fuel cellmodule of a solid oxide type.

BACKGROUND OF THE INVENTION

Conventionally, a fuel cell power generating system is constructed suchthat a raw material containing liquid fuel and water as its mainingredients is heated and decomposed by a burner of a reformer togenerate hydrogen gas, a fuel cell in which a fuel electrode and anoxygen electrode are disposed on both sides of an electrolyte layerintroduces the hydrogen gas generated by the reformer into the fuelelectrode to generate electric power and supplies steady electric powerto a specified load, a secondary battery supplies required electricpower to the load at least at the time of load starting or the time ofload variation, and power supply changeover means can switch betweenpower supplied from the fuel cell and power supplied from the secondarybattery (JP-A-6-140065). This fuel cell power generating system isconstructed such that fuel cell heating means for guiding combustion gasjetted from the burner of the reformer to the fuel cell is provided, andthe fuel cell is heated by the fuel cell heating means up to atemperature at which starting is enabled (electric power generation isenabled). Besides, the electrolyte layer is formed of a polymer filmhaving ion conductivity, and methanol is used as the liquid fuel.

In the fuel cell power generating system constructed as stated above,the time that elapses before the fuel cell starts the electric powergeneration can be greatly shortened by heating the fuel cell to apredetermined temperature by the combustion gas of the burner used atthe time of generation of hydrogen in the reformer, so that the powergeneration efficiency of the fuel cell can be improved. Besides, sincethe power supply from the secondary battery can be reduced by this, thenumber of secondary batteries can be decreased, and the compact andlightweight fuel cell power generating system can be obtained.

However, in the conventional fuel cell power generating system disclosedin JP-A-6-140065, since the raw material of the fuel gas supplied to thefuel cell is methanol, if this system is mounted in an automobile, therehas been a disadvantage that refueling can not be carried out in anormal gasoline station.

Besides, in the conventional fuel cell power generating system, sincethe working temperature of the fuel cell is relatively low, there hasbeen a problem that unless methanol is supplied to the fuel cell afterit is completely reformed into H₂ (hydrogen gas) by the reformer, thepower generation efficiency of the fuel cell is lowered.

Further, in the conventional fuel cell power generating system, sincethe electrolyte layer is formed of the polymer film, there has been aproblem that there is a fear that CO (carbon monoxide) is exhausted fromthe power generating cell, and the treatment of the carbon monoxide istroublesome.

SUMMARY OF THE INVENTION

A first object of the invention is to provide a hybrid power system inwhich gasoline, light oil or the like which can be fed in a normalgasoline station can be used as a raw material of a fuel gas supplied toa fuel cell module.

A second object of the invention is to provide a hybrid power system inwhich, since the working temperature of a fuel cell is relatively high,even if CO or CH₄ (methane gas) in addition to H₂ is directly suppliedto the fuel cell, a fuel cell module can efficiently generate electricpower.

A third object of the invention is to provide a hybrid power system inwhich, since the working temperature of a fuel cell is relatively high,hydrocarbon such as gasoline or light oil can be quickly reformed intolow hydrocarbon, CO or H₂ by using waste heat of an engine or a fuelcell.

The invention is, as shown in FIGS. 1 and 2, a hybrid power systemcomprising an engine 11 for generating mechanical power by combustion ofa mixture of a fuel gas obtained by vaporizing hydrocarbon and air, anda fuel cell module 13 in which plural electric power generating cells 24each including a solid electrolyte layer 29, and a fuel electrode layer31 and an air electrode layer 32 disposed on both sides of the solidelectrolyte layer 29 are laminated. The fuel gas obtained by reformingthe hydrocarbon is supplied to the fuel electrode layer 31, and the airor oxygen is supplied to the air electrode layer 32 so that electricpower can be generated at 930° C. or lower. One of or both of themechanical power generated by the engine 11 and the electric powergenerated by the fuel cell module 13 are outputted.

In the hybrid power system discussed above, when the engine 11 isstarted, the engine 11 generates the mechanical power. Besides, when thefuel cell module 13 reaches the temperature at which electric power canbe generated, the fuel gas obtained by reforming hydrocarbon, togetherwith the air or oxygen, is supplied to the fuel cell module 13, and thefuel cell module 13 starts electric power generation and generateselectric power. When the electric power generated by the fuel cellmodule 13 is sufficient, the engine 11 is stopped, and when the electricpower generated by the fuel cell module 13 is insufficient, the engine11 is started, and the mechanical power generated by the engine 11 isoutputted.

Further, as shown in FIG. 1, the fuel cell module 13 is heated by anexhaust gas exhausted from the engine 11, and starting becomes possible.Since the fuel cell module 13 is heated by the heat of the exhaust gasexhausted from the engine 11 up to the temperature at which startingbecomes possible, the fuel cell module 13 comes to be capable ofgenerating electric power.

Further, as shown in FIG. 1, the mechanical power generated by theengine 11 is converted into electric power by a generator 12 and isoutputted. When the engine 11 is started, the generator 12 is driven bythe engine 11 to generate the electric power. When the fuel cell module13 reaches the temperature at which electric power can be generated, thefuel gas obtained by reforming hydrocarbon, together with the air oroxygen, is supplied to the fuel cell module 13, and the fuel cell module13 starts electric power generation and generates the electric power.When the electric power generated by the fuel cell module 13 issufficient, the engine 11 is stopped, and when the electric powergenerated by the fuel cell module 13 is insufficient, the engine 11 isstarted and the mechanical power generated by the engine 11 is convertedinto the electric power by the generator 12 and is outputted.

Further, as shown in FIG. 1, a secondary battery 14 for storing theelectric power generated by one of or both of the fuel cell module 13and the generator 12. When the output is insufficient, the electricpower stored in the secondary battery 14 is outputted, and when theelectric power generated by the fuel cell module 13 or the generator 12is superfluous, the electric power generated by the fuel cell module 13or the generator 12 is stored in the secondary battery 14.

Further, as shown in FIG. 1, electric power generated by one or at leasttwo selected from the group consisting of the fuel cell module 13, thegenerator 12 and the secondary battery 14 is outputted to electricequipment 16, and the electric equipment 16 is driven by the electricpower. When the engine 11 is started, the generator 12 is driven by theengine 11 to generate the electric power, and this electric power isoutputted to the electric equipment 16. When the fuel cell module 13reaches the temperature at which electric power can be generated, thefuel gas obtained by reforming the hydrocarbon, together with the air oroxygen, is supplied to the fuel cell module 13, the fuel cell module 13starts electric power generation to generate electric power, and thiselectric power is supplied to the electric equipment 16. When theelectric power supplied from the fuel cell module 13 to the electricequipment 16 is sufficient, the engine 11 is stopped. When the electricpower outputted to the electric equipment 16 is insufficient, the engine11 is started, and the mechanical power generated by the engine 11 isconverted into the electric power by the generator 12 and is outputtedto the electric equipment 16. It is preferable that the electricequipment 16 is an electric motor.

Further, as shown in FIGS. 1 and 2, the fuel gas supplied to theelectric power generating cells 24 is reformed by the exhaust gasexhausted from the engine 11. Since the fuel gas before the supply tothe electric power generating cells 24 is heated by the heat of theexhaust gas exhausted from the engine 11 up to the temperature at whichthe fuel gas can be reformed, the fuel gas is reformed to become a lowhydrocarbon group most suitable for an electric power generatingoperation.

Further, as shown in FIGS. 1 and 2, a fuel preheating pipe 61 forpreheating the fuel gas and supplying it to the fuel electrode layer 31is provided in the fuel cell module 13, and an oxidant preheating pipe62 for preheating an oxidant gas and supplying it to the air electrodelayer 32 is provided in the fuel cell module 13. The oxidant preheatingpipe 62 is preheated by the exhaust gas exhausted from the engine 11,and the fuel preheating pipe 61 is also preheated by the exhaust gasexhausted from the engine 11, and hydrocarbon containing water vapor andpassing through the fuel preheating pipe 61 is reformed. After the fuelgas in the fuel preheating pipe 61 and the oxidant gas in the oxidantpreheating pipe 62 are heated by the exhaust gas of the engine 11, theyare supplied to the electric power generating cells 24. Therefore, theelectric power generating cells 24 are quickly heated up to the mostsuitable temperature and come to be capable of generating electricpower.

Further, as shown in FIG. 2, reforming particles are filled in the fuelpreheating pipe 61 at such a density that hydrocarbon can flow. The fuelgas containing water vapor comes in contact with the reforming particlesin the fuel preheating pipe 61, is reformed into the fuel gas of the lowhydrocarbon group or the like, and is supplied to the electric powergenerating cell 24.

Further, as shown in FIGS. 1 and 2, a reformer 64 is provided near thefuel cell module 13. The reformer 64 includes a reforming case 66 intowhich the exhaust gas of the engine 11 is introduced, and a reformingpipe 67 housed in the reforming case 66 and filled with reformingparticles at such a density that hydrocarbon can flow. The hydrocarbonpasses through the reforming pipe 67 so that the hydrocarbon is reformedinto the fuel gas of a low hydrocarbon group or the fuel gas of CO orH₂, and is supplied to the fuel cell module 13. When the hydrocarbon,together with water, flows into the reforming pipe 67 of the reformer64, the hydrocarbon and water are heated by the exhaust gas passingthrough the reforming case 66 and are vaporized, and become the fuel gascontaining water vapor. The fuel gas containing the water vapor comes incontact with the reforming particles in the reforming pipe 67, isreformed into the fuel gas of the low hydrocarbon group, or the like,and is supplied to the fuel cell module 13. Since the reformer 64 isprovided near the fuel cell module 13, the reformer 64 absorbs heatgenerated from the fuel cell module 13 at the time of electric powergeneration, and the fuel gas containing the water vapor is furtherefficiently reformed by the reforming particles in the reforming pipe 67into the fuel gas of the low hydrocarbon group, or the like.

Further, as shown in FIG. 2, a first auxiliary heater 81 for heating thereforming pipe 67 in the reformer 64 is provided. When the hydrocarbon,together with water, flows into the reforming pipe 67 of the reformer64, the hydrocarbon and the water are heated by not only the exhaust gasof the engine 11 passing through the reforming case 66, but also by thefirst auxiliary heater 81, and they are quickly vaporized and become thefuel gas containing water vapor. The fuel gas containing the water vaporcomes in contact with the reforming particles in the reforming pipe 67,and is quickly reformed into the fuel gas of the low hydrocarbon groupor the fuel gas of CO or H₂.

Further, as shown in FIG. 2, a second auxiliary heater 82 for heatingthe fuel preheating pipe 61 and the oxidant preheating pipe 62 in thefuel cell module 13 is provided.

When the fuel gas of the low hydrocarbon group, or the fuel gas of CO orH₂ flows into the fuel preheating pipe 61 in the fuel cell module 13,and the oxidant gas flows into the oxidant preheating pipe 62, the fuelgas and the oxidant gas are heated by not only the exhaust gas of theengine 11 passing through the fuel cell module 13, but also the secondauxiliary heater 82, and are heated to a relatively high temperaturemost suitable for electric power generation. Then, they are supplied tothe electric power generating cells 24.

Further, as shown in FIGS. 1 and 2, a fuel supply pipe 68 is connectedto a base end of the fuel preheating pipe 61, and a fuel injector 73 forspraying the hydrocarbon with a high melting point, which is liquid atroom temperature, among hydrocarbons and supplying it to the fuelpreheating pipe 61 is provided to the fuel supply pipe 68.

Further, as shown in FIGS. 1 and 2, a water supply pipe 74 is connectedto the fuel supply pipe 68, and a water injector 76 for spraying waterand supplying it to the fuel supply pipe 68 is provided to the watersupply pipe 74. Thus, the liquid fuel or water can be quickly vaporized.

Further, as shown in FIG. 1, a module temperature sensor 72 fordetecting the temperature of the fuel cell module 13 is inserted in thefuel cell module 13. When the module temperature sensor 72 detects thatthe fuel cell module 13 is heated by the exhaust gas of the engine 11 toreach the temperature at which the fuel cell module 13 can generateelectric power, a controller 77 controls the fuel cell module 13 tostart an electric power generating operation. When the fuel cell module13 has a low temperature as at a time immediately after the start of theengine 11, the state is kept in which electric power generation by thefuel cell module 13 is stopped. When the temperature sensor 72 detectsthat the fuel cell module 13 is heated by the exhaust gas of the engine11 and reaches the temperature at which electric power can be generated,the electric power generation by the fuel cell module 13 is started, sothat efficient electric power generation by the fuel cell module 13becomes possible.

It is also preferable that on the basis of a load of the electricequipment 16, the controller 77 controls one or at least two selectedfrom the group consisting of the engine 11, the fuel cell module 13, andthe secondary battery 14.

The structure may also be such that an oxidant flow rate adjusting valve71 is provided in an oxidant supply pipe 69 provided at a base end ofthe oxidant preheating pipe 62, a reformer temperature sensor detectstemperature of the reformer 64, and the controller 77 controls the fuelinjector 73, the water injector 76, the oxidant flow rate adjustingvalve 71, the first auxiliary heater 81, and the second auxiliary heater82 on the basis of respective detection outputs of the moduletemperature sensor 72 and the reformer temperature sensor.

The structure may be such that a communicating pipe 63 f for connectingan inside chamber 63 d of a cell case 63 housing the fuel cell module 13and an outside chamber 63 e is provided with a first motor valve 91 foropening and closing the communicating pipe 63 f. An upstream sideexhaust pipe 21 a for connecting the engine 11 and the fuel cell module13 is provided with a second motor valve 92 for opening and closing theupstream side exhaust pipe 21 a. An upstream side branch pipe 21 c forconnecting the upstream side exhaust pipe 21 a and the reformer 64 isprovided with a third motor valve 93 for opening and closing theupstream side branch pipe 21 c. The controller 77 controls the first tothe third motor valves 91 to 93 on the basis of respective detectionoutputs of the module temperature sensor 72 and the reformer temperaturesensor.

Incidentally, it is preferable that an automobile, a ship, a train, anairplane, a motorcycle or a construction equipment is driven by one ofor both of the mechanical powers generated by the electric equipment 16and the engine 11.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a hybrid power system of anembodiment of the invention.

FIG. 2 is a longitudinal sectional view of a fuel cell module used forthis system.

FIG. 3 is a sectional view taken along line A—A of FIG. 4 of a fuel cellused for the fuel cell module.

FIG. 4 is a sectional view taken along line B—B of FIG. 3.

FIG. 5 is a sectional view taken along line C—C of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

Next, an embodiment of the invention will be described with reference tothe drawings.

As shown in FIG. 1, a hybrid power system of the invention is mounted inan automobile. This hybrid power system includes an engine 11 usinggasoline as fuel, a generator 12 an input shaft 12 a which is coupledwith a crank shaft 11 a of the engine 11, a fuel cell module 13 whichcan generate electric power at 930° C. or lower, a secondary battery 14,and an electric motor 16. An intake pipe 18 is connected to an intakeport of the engine 11 through an intake manifold 17, and an upstreamside exhaust pipe 21 a of an exhaust pipe 21 is connected to an exhaustport of the engine 11 through an exhaust manifold 19. A carburetor 22for vaporizing gasoline to supply it to the intake pipe 18 is providedmidway in the intake pipe 18, and a tip end of a refueling pipe 23, abase end of which is connected to a fuel tank (gasoline is stored), isconnected to the carburetor 22. Gasoline vaporized by the carburetor 22is mixed with air, is supplied to a cylinder (not shown) of the engine11 through the intake pipe 18 and the intake manifold 17, and isexplosively burned in this cylinder to drive a piston (not shown), sothat the crank shaft 11 a is rotated. The generator 12 is constructedsuch that the rotation force of the crank shaft 11 a is transmitted tothe input shaft 12 a to generate electric power. Incidentally, theinvention can also be applied to a rotary engine having a triangularrotor and an eccentric shaft, not a reciprocating engine having acylindrical piston and a crank shaft.

It is preferable that the fuel cell module 13 can generate electricpower within a range of 300 to 900° C. As shown in FIG. 2, it includes afuel cell 26 having (n+1) laminated electric power generating cells 24,and a fuel distributor 27 and an air distributor 28 respectivelyprovided near the fuel cell 26. Here, n is a positive integer. Theelectric power generating cell 24 includes a disk-shaped solidelectrolyte layer 29, and a disk-shaped fuel electrode layer 31 and airelectrode layer 32 disposed on both sides of the solid electrolyte layer29. N separators 33 in total, each formed into a square plate shape byconductive material, is put between the fuel electrode layer 31 of theith (i=1, 2, . . . , n) electric power generating cell 24 and the airelectrode layer 32 of the (i+1)th electric power generating cell 24adjacent to this fuel electrode layer 31. A porous fuel electrodecurrent collector 34 formed into a disk shape and having conductivity isput between the fuel electrode layer 31 of the ith electric powergenerating cell 24 and the jth (j=1, 2, . . . , n) separator 33, and aporous air electrode current collector 36 formed into a disk shape andhaving conductivity is put between the air electrode layer 32 of the(i+1)th electric power generating cell 24 and the jth separator 33.Further, a single first end plate 41 formed into a square plate shape byconductive material is laminated on the air electrode layer 32 of thefirst electric power generating cell 24 through the air electrodecurrent collector 36, and a single second end plate 42 formed into asquare plate shape by conductive material is laminated on the fuelelectrode layer 31 of the (n+1)th electric power generating cell 24through the fuel electrode current collector 34. Incidentally, the solidelectrolyte layer, the fuel electrode layer, the air electrode layer,the fuel electrode current collector and the air electrode currentcollector may be formed into a polygonal plate shape, such as a squareplate shape, a hexagonal plate shape or an octagonal plate shape, notthe disk shape. Besides, the separator, the first end plate and thesecond end plate may be formed into a disk plate shape or a polygonalplate shape, such as a rectangular plate shape, a hexagonal plate shapeor an octagonal plate shape, not the square plate shape.

The solid electrolyte layer 29 is formed of an oxide ion conductor.Specifically, it is an oxide ion conductor expressed by a generalformula (1): Ln1AGaB1B2B3O. Where, in the above general formula (1), Ln1denotes one or not less than two elements selected from the groupconsisting of La, Ce, Pr, Nd and Sm and is contained at 43.6 to 51.2 wt.%, A denotes one or not less than two elements selected from the groupconsisting of Sr, Ca and Ba and is contained at 5.4 to 11.1 wt. %, Ga iscontained at 20.0 to 23.9 wt. %, B1 denotes one or not less than twoelements selected from the group consisting of Mg, Al and In, B2 denotesone or not less than two elements selected from the group consisting ofCo, Fe, Ni and Cu, and B3 denotes one or not less than two elementsselected from the group consisting of Al, Mg, Co, Ni, Fe, Cu, Zn, Mn andZr. When B1 and B3 or B2 and B3 are not the same element, B1 iscontained at 1.21 to 1.76 wt. %, B2 is contained at 0.84 to 1.26 wt. %,and B3 is contained at 0.23 to 3.08 wt. %. When B1 and B3 or B2 and B3are the same element, the total of a B1 content and a B3 content is 1.41to 2.70 wt. %, and the total of a B2 content and a B3 content is 1.07 to2.10 wt. %.

Besides, the solid electrolyte layer 29 may be formed of an oxide ionconductor expressed by a general formula (2)Ln1_(1-x)A_(x)Ga_(1-y-z-w)B1_(y)B2_(z)B3_(w)O_(3-d). Where, in the abovegeneral formula (2), Ln1 denotes one or not less than two elementsselected from the group consisting of La, Ce, Pr, Nd and Sm, A denotesone or not less than two elements selected from the group consisting ofSr, Ca and Ba, B1 denotes one or not less than two elements selectedfrom the group consisting of Mg, Al and In, B2 denotes one or not lessthan two elements selected from the group consisting of Co, Fe, Ni andCu, B3 denotes one or not less than two elements selected from the groupconsisting of Al, Mg, Co, Ni, Fe, Cu, Zn, Mn and Zr, x is 0.05 to 0.3, yis 0.025 to 0.29, z is 0.01 to 0.15, w is 0.01 to 0.15, y+z+w is 0.035to 0.3, and d is 0.04 to 0.3. By forming the solid electrolyte layer 29of the oxide ion conductor as set forth above, it becomes possible toperform an electric power generating operation at a relatively lowtemperature of 650±50° C. without lowering the electric power generationefficiency of the fuel cell 26.

The fuel electrode layer 31 is formed of metal such as Ni, or cermetsuch as Ni—YSZ, or is formed to be porous by a mixed body of Ni and acompound expressed by a general formula (3): Ce_(1-m)D_(m)O₂. Where, inthe general expression (3), D denotes one or not less than two elementsselected from the group consisting of Sm, Gd, Y and Ca, m denotes anatomic ratio of D element and is set to be within a range of 0.05 to0.4, preferably 0.1 to 0.3.

The air electrode layer 32 is formed to be porous by an oxide ionconductor expressed by a general formula (4):Ln2_(1-x)Ln3_(x)E_(1-y)Co_(y)O_(3+d). Where, in the above generalformula (4), Ln2 denotes one or both elements of La and Sm, Ln3 denotesone or both elements of Ba, Ca and Sr, and E denotes one or bothelements of Fe and Cu. Besides, x denotes an atomic ratio of Ln3 and isset to be within a range of larger than 0.5 and less than 1.0. Besides,y denotes an atomic ratio of Co element and is set to be within a rangeof larger than 0 and not larger than 1.0, preferably not less than 0.5and not larger than 1.0. Besides, d is set to be within a range of notless than −0.5 and not larger than 0.5.

An example of a manufacturing method of the electric power generatingcell 24 will be described below. First, as raw material powder,respective powders of La₂O₃, SrCO₃, Ga₂O₃, MgO, and CoO are weighed andmixed to realize La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.15)CO_(0.05)O_(2.8), andthen preliminary firing is performed at 1100° C. to form a calcinatedbody. Next, after this calcinated body is pulverized, a specifiedbinder, solvent and the like are added and mixed to prepare slurry, anda green sheet is prepared from this slurry by a doctor blade method.Next, this green sheet is sufficiently dried in the air and is cut intoa predetermined size, and then, it is sintered at 1450° C. so that thesolid electrolyte layer 29 is obtained. After an NiO powder and a(Ce_(0.8)Sm_(0.2)) O₂ powder are mixed so that the volume ratio of Niand (Ce_(0.8)Sm_(0.2))O₂ becomes 6:4, this mixed powder is sintered onone surface of the solid electrolyte layer 29 at 1100° C. to form thefuel electrode layer 31. Further, (Sm_(0.5)Sr_(0.5))CoO₃ is sintered onthe other surface of the solid electrolyte layer 29 at 1000° C. to formthe air electrode layer 32. In this way, the electric power generatingcell 24 is fabricated.

It is preferable that the separator 33 is formed of stainless steel,nickel base alloy or chromium base alloy. For example, there areenumerated SUS316, Inconel 600, Hastelloy X (trade name of HaynesStellite Co.), Haynes alloy 214 and the like. Besides, a fuel supplypassage 43, an air supply passage 44 (oxidant supply passage) and pluralinsertion holes 33 a are formed in the separator 33 (FIGS. 3 and 4). Thefuel supply passage 43 includes a first fuel hole 43 a headed from theouter peripheral surface of the separator 33 to substantially thecenter, and a second fuel hole 43 b communicating with the first fuelhole 43 a and facing the fuel electrode current collector 34 fromsubstantially the center of the separator 33. Besides, the air supplypassage 44 includes a single first air hole 44 a which is formed toextend in the direction orthogonal to the thickness direction of theseparator 33, a base end of which is opened to the outer peripheralsurface of the separator 33, and a tip end of which is closed, pluralsecond air holes 44 b which extend in the direction orthogonal to thethickness direction of the separator 33, which are formed to be spacedfrom one another at predetermined intervals, which communicate with thesingle air hole 44 a, and both ends of which are closed, and a largenumber of third air holes 44 c formed at predetermined intervals in thesurface opposite to the air electrode current collector 36 of theseparator 33 and to communicate with the second air holes 44 b.

The plural second air holes 44 b are formed to be parallel to oneanother from a side surface adjacent to one side surface of theseparator 33 on which the base end of the first air hole 44 a is formed.Then, a closing plate 45 is bonded to the adjacent side surface, so thatthey become long holes both ends of which are closed. The pluralinsertion holes 33 a are formed to be parallel with the first fuel hole43 a and the second air hole 44 b so that they do not communicate withany of the fuel supply passage 43 and the air supply passage 44, andfirst heaters 46 are respectively inserted in these insertion holes 33 a(FIG. 4). Besides, three slits 33 b are spirally formed fromsubstantially the center of the separator 33 on the surface of theseparator 33 opposite to the fuel electrode current collector 34 (FIG.5), and the depths of these slits 33 b are formed to be the same overthe whole length. Incidentally, the number of the slits may be two orfour or more, not three. Besides, the depths of the slits may be formedso that they gradually become deep or shallow as they go away from thecenter of the separator.

Referring back to FIG. 3, the fuel electrode current collector 34 isformed of stainless steel, nickel base alloy or chromium base alloy, ornickel, silver, silver alloy or copper to be porous. In the case whereit is formed of stainless steel, nickel base alloy or chromium basealloy, it is preferable to perform nickel plating, silver plating,silver plating through nickel under plating, or copper plating. The airelectrode current collector 36 is formed of stainless steel, nickel basealloy or chromium base alloy, or silver, silver alloy or platinum to beporous. In the case where it is formed of stainless steel, nickel basealloy, or chromium base alloy, it is preferable to perform silverplating, silver plating through nickel under plating, or platinumplating. Incidentally, in the case where a fuel gas of a low hydrocarbongroup, such as CH₄, is used as a reformed fuel gas, the fuel electrodecurrent collector is formed of stainless steel, nickel base alloy, orchromium base alloy, which is plated with nickel, or nickel. In the casewhere CO or H₂ is used as the fuel gas, the fuel electrode currentcollector is formed of stainless steel, nickel base alloy or chromiumbase alloy, which is plated with silver, plated with silver throughnickel under plating, or plated with copper, or silver, silver alloy orcopper.

An example of a manufacturing method of the fuel electrode currentcollector 34 will be described below. First, after atomized powder ofstainless steel or the like and HPMC (water soluble resin binder) arekneaded, distilled water and an additive (n-hexane (organic solvent),DBS (surface active agent), glycerol (plasticizer), etc.) are added andkneaded to prepare mixed slurry. Next, after a compact is formed fromthis mixed slurry by a doctor blade method, foaming, degreasing andsintering are performed under predetermined conditions to obtain aporous plate. Further, this porous plate is cut into parts ofpredetermined sizes to prepare the fuel electrode current collectors 34.Incidentally, in the case where the atomized powder of stainless steelis used, the surface is subjected to nickel plating, chromium plating orsilver plating. In addition, the air electrode current collector 36 isalso fabricated in substantially the same manner as the fuel electrodecurrent collector 34.

The first end plate 41 and the second end plate 42 are formed of thesame material as the separator 33 to have the same shape (square plateshape). An air supply passage 48 and plural insertion holes (not shown)are formed in the first end plate 41, and a fuel supply passage 47 andplural insertion holes (not shown) are formed in the second end plate42. The air supply passage 48 is formed similarly to the air supplypassage 44, and includes a single first air hole 48 a which is formed toextend in the direction orthogonal to the thickness direction of thefirst end plate 41, the base end of which is opened to the outerperipheral surface of the first end plate 41, and the tip end of whichis closed, plural second air holes (not shown) which extend in thedirection orthogonal to the thickness direction of the first end plate41, which are formed to be spaced from one another at predeterminedintervals, which communicate with the single first air hole, and bothends of which are closed, and a large number of third air holes (notshown) formed at predetermined intervals in the surface of the first endplate 41 opposite to the air electrode current collector 36 and tocommunicate with the second air holes. In addition, the fuel supplypassage 47 is formed similarly to the fuel supply passage 43, andincludes a first fuel hole 47 a headed to substantially the center fromthe outer peripheral surface of the second end plate 42, and a secondfuel hole 47 b communicating with the first fuel hole 47 a and facingthe fuel electrode current collector 34 from substantially the center ofthe second end plate 42.

The plural second air holes formed in the first end plate 41 are formedto be parallel with one another from the side surface adjacent to oneside surface of the first end plate 41 on which the base end of thefirst air hole is formed. Then, the closing plate 45 is bonded to theadjacent side surface so that they become long holes both ends of whichare closed. The plural insertion holes of the first end plate 41 areformed to be parallel with the second air holes so as not to communicatewith the air supply passage 48, and the heaters (not shown) arerespectively inserted into these insertion holes. The plural insertionholes of the second end plate 42 are formed to be parallel with thefirst fuel hole 47 a so as not to communicate with the fuel supplypassage 47, and heaters (not shown) are respectively inserted into theseinsertion holes. Three slits 42 b are spirally formed from substantiallythe center of the second end plate 22 on the upper surface of the secondend plate 42 (that is, the opposite surface of the second end plate 42to the fuel electrode current collector 34 (FIG. 3)). The depths ofthese slits 42 b are formed to be the same over the whole length.Incidentally, the number of the slits may be two or four or more, notthree. Besides, the depths of the slits may be formed to graduallybecome deep or shallow as they go away from the center of the separator.

Further, through holes 33 c through which bolts (not shown) can beinserted are formed at four corners of the separator 33, the first endplate 41 and the second end plate 42 (FIGS. 4 and 5). When the (n+1)electric power generating cells 24, the n separators 33, the (n+1) fuelelectrode current collectors 34, the (n+1) air electrode currentcollectors 36, the single first end plate 41, and the single second endplate 42 are laminated, the bolts are respectively inserted through thethrough holes 33 c formed at the four corners of the separator 33, thefirst end plate 41, and the second end plate 42, and then nuts arescrewed to the tip ends of these bolts, so that the fuel cell 26 isfixed in the laminated state.

Referring back to FIG. 2, the fuel distributor 27 and the airdistributor 28 are respectively provided to extend in the laminatedirection of the electric power generating cells 24, and are formed tohave cylindrical shapes both ends of which are closed. The fueldistributor 27 communicates with and is connected to the first fuelholes 43 a of the fuel supply passages 43 of the n separators 33 and thefirst fuel hole 47 a of the fuel supply passage 47 of the single secondend plate 42 through (n+1) fuel short pipes 51. The air distributor 28communicates with and is connected to the first air holes 44 a of theair supply passages 44 of the n separators 33 and the first air hole 48a of the air supply passage 48 of the single first end plate 41 through(n+1) air short pipes 52. In this embodiment, the fuel distributor 27,the air distributor 28, the fuel short pipes 51 and the air short pipes52 are formed of conductive material such as stainless steel.

A fuel insulating pipe (not shown) formed of electrical insulatingmaterial such as alumina is put between the fuel short pipe 51 and thefuel distributor 27 in order to secure electrical insulation between thefuel short pipe 51 and the fuel distributor 27, and a gap of these issealed with a fuel sealing member (not shown) such as glass. Besides, anair insulating pipe (not shown) formed of electrical insulating materialsuch as alumina is put between the air short pipe 52 and the airdistributor 28 in order to secure electrical insulation between the airshort pipe 52 and the air distributor 28, and a gap of these is sealedwith an air sealing member (not shown) such as glass.

A pair of electrode terminals 58, 58 (electrode rods in this embodiment)are electrically connected to the center of the upper surface of thefirst end plate 41 and the center of the lower surface of the second endplate 42, respectively. The fuel preheating pipe 61 is connected to theupper outer peripheral surface of the fuel distributor 27, and this fuelpreheating pipe 61 is spirally wound to be separated from the outerperipheral surface of the fuel cell 26 by a predetermined space andaround the axial line of the pair of electrode terminals 58, 58.Besides, the air preheating pipe 62 is connected to the upper outerperipheral surface of the air distributor 28, and this air preheatingpipe 62 is spirally wound to be separated from the outer peripheralsurface of the fuel cell 26 by a predetermined space and around theaxial line of the pair of electrode terminals 58, 58. The spiral radiusof the fuel preheating pipe 61 is formed to be smaller than the spiralradius of the air preheating pipe 62.

The fuel cell 26, together with the fuel distributor 27, the airdistributor 28, the fuel preheating pipe 61, and the air preheating pipe62, is contained in the cell case 63. The fuel cell 26, the fueldistributor 27, and the air distributor 28 are separated from the fuelpreheating pipe 61 and the air preheating pipe 62 by a cylindricalpartition plate 63 c into an inside chamber 63 d and an outside chamber63 e. The inside chamber 63 d and the outside chamber 63 e are made tocommunicate with each other through a communicating pipe 63 f. Anexhaust gas introduction port 63 a for introduction of the exhaust gasof the engine 11 into this case 63 is formed at the upper part of theouter peripheral surface of the cell case 63, and an exhaust gas exhaustport 63 b for exhaustion of the exhaust gas introduced in this case 63,together with the fuel gas and air exhausted from the fuel cell 26, tothe outside of the case 63 is formed at the lower part of the outerperipheral surface of the cell case 63. The upstream side exhaust pipe21 a is connected to the exhaust gas introduction port 63 a, and thedownstream side exhaust pipe 21 b is connected to the exhaust gasexhaust port 63 b. Besides, a reformer 64 is provided at the outerperipheral surface of the cell case 63. This reformer 64 includes areforming case 66 into which the exhaust gas of the engine 11 isintroduced, and a reforming pipe 67 contained in the reforming case 66and heated by the exhaust gas of the engine 11. An exhaust gas inlet 66a for introduction of the exhaust gas of the engine 11 and an exhaustgas outlet 66 b for exhaustion of the exhaust gas of the engine 11 areprovided in the reforming case 66. An upstream side branch pipe 21 cbranching from the upstream side exhaust pipe 21 a is connected to theexhaust gas inlet 66 a, and a downstream side branch pipe 21 d isconnected to the exhaust gas outlet 66 b. A gasoline supply pipe 68branching from the refueling pipe 23 is connected to the base end of thefuel preheating pipe 61 through the reforming pipe 67. Further,reforming particles (not shown) are filled in the reforming pipe 67 atsuch a density that the fuel gas of a low hydrocarbon group, such asgasoline, light oil or CH₄, can flow. It is preferable that thereforming particles are formed of elements or oxides containing one orat least two selected from the group consisting of Ni, NiO, Al₂O₃, SiO₂,MgO, CaO, Fe₂O₃, Fe₃O₄, V₂O₃, NiAl₂O₄, ZrO₂, SiC, Cr₂O₃, ThO₂, Ce₂O₃,B₂O₃, MnO₂, ZnO, Cu, BaO and TiO₂.

Reference numeral 69 of FIGS. 1 and 2 denotes an air supply pipeconnected to the base end of the air preheating pipe 62 in the cell case63 and for supplying air (or oxygen) to the air preheating pipe 62, andan air flow rate adjusting valve 71 is provided in this pipe 69 (FIG.1). A module temperature sensor 72 for detecting the temperature of thefuel cell module 13 is inserted in the fuel cell module 13 (FIGS. 1 and2), and a gasoline injector 73 is provided to the gasoline supply pipe68 (FIG. 1). A water supply pipe 74 is connected to the gasoline supplypipe 68 at the downstream side of the gasoline injector 73, and a waterinjector 76 is provided to the water supply pipe 74. The gasolineinjector 73 is constructed to spray high melting point hydrocarbon(light oil, etc.), which is liquid at room temperature, to supply it tothe reforming pipe 67, and the water injector 76 is constructed to spraywater to supply it to the gasoline supply pipe 68.

A first auxiliary heater 81 for heating the reforming pipe 67 isprovided in the reformer 64, and a second auxiliary heater 82 forheating the fuel preheating pipe 61 and the air preheating pipe 62 inthe outside chamber 63 e is provided in the cell case 63. Besides, areformer temperature sensor (not shown) for detecting the temperature ofthis reformer 64 is provided in the reformer 64. The first auxiliaryheater 81 includes a first case 81 a attached to the lower surface ofthe reforming case 66 and a first burner 81 b inserted in this firstcase 81 a. The second auxiliary heater 82 includes a second case 82 aattached to the lower surface of the cell case 63 and a second burner 82b inserted in this second case 82 a. A structure is adopted such thatlight oil is supplied to the first and the second burners 81 b and 82 b.Further, first to third motor valves 91 to 93 are provided in theupstream side exhaust pipe 21 a, the upstream side branch pipe 21 c andthe communicating pipe 63 f. The first to the third motor valves 91 to93 include valve bodies 91 a to 93 a for opening and closing the pipes21 a, 21 c and 63 f, and first to third motors 91 b to 93 b for drivingthese valve bodies 91 a to 93 a.

The detection outputs of the module temperature sensor 72 and thereformer temperature sensor are respectively connected to the controlinput of a controller 77, and the control outputs of the controller 77are respectively connected to the air flow rate adjusting valve 71, thegasoline injector 73, the water injector 76, an electric powersupply-demand selector 78, the heater 46, the first auxiliary heater 81,the second auxiliary heater 82, the first to the third motors 91 b to 93b, and the carburetor 22. The generator 12, the fuel cell module 13, thesecondary battery 14 and the electric motor 16 are electricallyconnected to the electric power supply-demand selector 78. An engineautomatic on/off device (not shown) for automatically starting orstopping the engine 11 is provided in the engine 11, and this device isconnected to the control output of the controller 77. Further, thesecondary battery 14 is constructed to store electric power suppliedfrom one of or both of the generator 12 and the fuel cell module 13 bythe electric power supply-demand selector 78, and electric power issupplied to the electric motor 16 by the electric power supply-demandselector 78 from one or at least two selected from the group consistingof the generator 12, the fuel cell module 13 and the secondary battery14. Incidentally, reference numeral 79 of FIG. 2 denotes an insulatingring for electrically insulating the cell case 63 from the pair ofelectrode terminals 58, 58.

The operation of the hybrid power system constructed as stated abovewill be described.

When the engine 11 is started, the engine 11 generates mechanical power,and this mechanical power is transmitted from the crank shaft 11 a tothe input shaft 12 a of the generator 12, so that the generator 12 isdriven to generate electric power. Since the temperature of the fuelcell module 13 immediately after the starting of the engine 11 does notreach the temperature (for example, 650° C.) at which electric power canbe generated, the controller 77 keeps the gasoline injector 73, thewater injector 76, and the first motor valve 91 in the closed state onthe basis of the respective detection outputs of the module temperaturesensor 72 and the reformer temperature sensor (not shown), and keeps theair flow rate adjusting valve 71, the second motor valve 92 and thethird motor valve 93 in the open state. The controller 77 furthercontrols the electric power supply-demand selector 78 to supply theelectric power generated by the generator 12 and the electric powerstored in the secondary battery 14 to the electric motor 16 and to causethe automobile to run. Here, the air is made to flow to the fuel cellmodule 13 immediately after the starting of the engine 11 since the airheated by the air (oxidant) preheating pipe 62 is uniformly blown to thewhole surface of the electric power generating cell 24 from theseparator 33 and the second end plate 42, so that heating can also beperformed from the inside of the fuel cell 26. While the temperature ofthe fuel cell 26 is kept uniform, it can be quickly heated. Further, inthe case where the quick electric power generating operation of the fuelcell module 13 is required, power is applied to the heater 46.

On the other hand, when the engine 11 is started, a high temperatureexhaust gas is exhausted from the engine 11. Nearly half of the exhaustgas is supplied to the outside chamber 63 e in the cell case 63 throughthe exhaust manifold 19 and the upstream side exhaust pipe 21 a, and theremaining half is supplied into the reforming case 66 through theupstream side branch pipe 21 c branching from the upstream side exhaustpipe 21 a. When the module sensor 72 detects that the fuel cell 26 inthe cell case 63 is heated by the exhaust gas of the engine 11 or theexhaust gas of the engine 11 and the heater 46 to reach the temperatureat which electric power can be generated, the controller 77 opens thegasoline injector 73, the water injector 76, and the first motor valve91 at predetermined opening degrees, respectively, on the basis of thedetection output of the module temperature sensor 72. If power is beingapplied to the heater 46, the application of the power to the heater 46is stopped. When the gasoline injector 73 and the water injector 76 areopened, gasoline and water flow into the reforming pipe 67 of thereformer 64 are heated by the exhaust gas passing through the reformingcase 66 to be vaporized, and become a fuel gas containing water vapor.

The fuel gas containing the water vapor comes in contact with thereforming particles in the reforming pipe 67 to be reformed into the lowhydrocarbon group, and flows into the fuel preheating pipe 61 in thecell case 63. This reformed fuel gas spirally goes round the outerperipheral surface of the fuel cell 26 in the fuel preheating pipe 61and exchanges heat with the high temperature exhaust gas so that it isfurther heated. Then, it is supplied to the fuel distributor 27, and theair flowing into the air preheating pipe 62 from the air supply pipe 69spirally goes round the outer peripheral surface of the fuel cell 26 inthe air preheating pipe 62 and exchanges heat with the high temperatureexhaust gas, so that it is heated. Then, it is supplied to the airdistributor 28. Incidentally, when it takes a long time before the fuelcell 26 in the cell case 63 reaches the temperature at which electricpower can be generated by heating of only the exhaust gas of the engine11 and the heater 46, the controller 77 operates the first and thesecond auxiliary heaters 81 and 82.

When the fuel gas heated up to the temperature most suitable for theelectric power generation and reformed is introduced into the fueldistributor 27, this fuel gas passes through the fuel short pipe 51 andthe fuel supply passages 43 and 47, and is discharged from substantiallythe center of the separator 33 and the second end plate 42 toward thecenter of the fuel electrode current collector 34. By this, the fuel gaspasses through pores in the fuel electrode current collector 34 and isquickly supplied to substantially the center of the fuel electrode layer31, and is further guided by the slit 33 b of the separator 33 and theslit 42 b of the second end plate 42 to spirally flow from substantiallythe center of the fuel electrode layer 31 to the outer peripheral edge.At the same time, when the air heated up to the temperature mostsuitable for electric power generation is introduced into the airdistributor 28, this air passes through the air short pipe 52 and theair supply passages 44 and 48, and is discharged like a shower from thelarge number of third air holes 44 c of the separator 33 and the largenumber of third air holes (not shown) of the first end plate 41 towardthe air electrode current collector 36. By this, the air passes throughpores in the air electrode current collector 36 and is substantiallyuniformly supplied to the air electrode layer 32.

The air supplied to the air electrode layer 32 passes through pores inthe air electrode layer 32 and reaches the vicinity of an interfacerelative to the solid electrolyte layer 29, and oxygen in the airreceives electrons from the air electrode layer 32 in this portion andis ionized into oxide ions (O²⁻). This oxide ion diffuses and moves inthe solid electrolyte layer 29 toward the direction of the fuelelectrode layer 31, and when reaching the vicinity of an interfacerelative to the fuel electrode layer 31, it reacts with the fuel gas inthis portion to produce a reaction product (for example, H₂O), andreleases electrons to the fuel electrode layer 31. A current isgenerated by extracting the electrons to the fuel electrode currentcollector 34, and the electric power can be obtained.

As set forth above, the fuel gas is discharged from substantially thecenter of the separator 33 and substantially the center of the secondend plate 42 and is guided by the slits 33 b and 42 b, so that thereaction passage of the fuel gas becomes long. As a result, the fuel gascollides with the fuel electrode layer 31 many times until the fuel gasreaches the separator 33 and the outer peripheral edge of the second endplate 42, so that the number of reactions is increased and theperformance of the fuel cell 26 can be improved. Accordingly, as theouter diameters of the separator 33 and the second end plate 42 becomelarge, the reaction passage of the fuel gas becomes long, and the numberof reactions is increased by this, which results in the increase ofoutput of the fuel cell 26. Incidentally, (n+1) electric powergenerating cells 24 are connected in series through the separators 33formed by a conductive material, the fuel electrode current collectors34, and the air electrode current collectors 36, and the pair ofelectrode terminals 58 and 58 are provided at the first end plate 41 andthe second end plate 42 on both ends of the fuel cell 26, so that largeelectric power can be extracted from these electrode terminals 58 and58.

High temperature fuel gas is exhausted from the outer peripheral surfaceof the fuel electrode layer 31, and high temperature air is exhaustedfrom the outer peripheral surface of the air electrode layer 32, so thatthese mixed gases pass through the communicating pipe 63 f and flow intothe outside chamber 63 e, and the fuel gas in the fuel preheating pipe61 and the air in the air preheating pipe 62 are heated. As a result,the controller 77 closes the second motor valve 91 to stop theintroduction of the exhaust gas of the engine 11 into the cell case 63after a predetermined time has passed since the fuel cell 26 started theelectric power generation. On the other hand, when the fuel cell module13 generates electric power, the controller 77 controls the electricpower supply-demand selector 78 to supply the electric power from thefuel cell module 13 to the electric motor 16, and controls thecarburetor to stop the supply of gasoline to the intake pipe 18 andstops the engine 11. When the output of the electric motor 16 isinsufficient, or when the charging quantity of the secondary battery 14is insufficient, the controller 77 starts the engine 11, and electricpower is supplied from the generator 12 to the electric motor 16 or thesecondary battery 14.

Incidentally, in the above embodiment, although the solid electrolytelayer is formed of the oxide ion conductor expressed by the generalformula (1): Ln1AGaB1B2B3O or the general formula (2):Ln1_(1-x)A_(x)Ga_(1-y-z-w)B1_(y)B2_(z)B3_(w)O_(3-d), it may be formed ofan oxide ion conductor made of YSZ (stabilized zirconia added withyttria), or may be formed of a proton conductor (ceria etc.).

In the above embodiment, although the electric motor is cited as theelectric equipment, the electric equipment may be a computer, a lamp(illuminating lamp), an electric heater or the like.

In the above embodiment, the mechanical power generated by the engine isconverted into the electric power by the generator, the electric motoris driven by one of or both of this electric power and the electricpower generated by the fuel cell module, and the automobile is caused torun by the mechanical power generated by the electric motor. However, aship, a train, an airplane (propeller type), a motor cycle, aconstruction equipment or the like may be driven. In addition, a firstclutch is connected to a crank shaft of the engine, and a second clutchis connected to an output shaft of the electric motor driven by theelectric power generated by the fuel cell module, and an automobile, aship, a train, an airplane (propeller type), a motor cycle, aconstruction equipment or the like may be driven by one of or both ofthe mechanical powers generated by the electric motor and the engine.

According to the above embodiment, although gasoline is supplied to theengine and the reformer, light oil or propane may be supplied.

In the above embodiment, the reforming particles are filled in thereforming pipe of the reformer at such a density that gasoline or thelike can flow, and the gasoline or the like is reformed into the fuelgas of the low hydrocarbon group by the reforming particles. However,the reforming particles are filled in the fuel preheating pipe at such adensity that gasoline or the like can flow, and if the gasoline or thelike can be reformed by the reforming particles into the fuel gas of thelow hydrocarbon group, the reformer becomes unnecessary.

Further, in the above embodiment, although the separator is formed ofstainless steel, nickel base steel or chromium base alloy, it may beformed of ceramic having conductivity, such as lanthanum chromite(La_(0.9)Sr_(0.1)CrO₃).

INDUSTRIAL APPLICABILITY

As described above, according to the invention, power is generated bycombustion of the mixture of the fuel gas obtained by vaporizinghydrocarbon and the air, the fuel gas obtained by reforming thehydrocarbon is supplied to the fuel electrode layer of the fuel cellmodule in which the plural electric power generating cells eachincluding the solid electrolyte layer, and the fuel electrode layer andthe air electrode layer disposed on both sides thereof are laminated,and air or oxygen is supplied to the air electrode layer so thatelectric power is generated at 930° C. or lower. One of or both of themechanical power generated by the engine and the electric powergenerated by the fuel cell module are outputted. Accordingly, when theengine is started, the engine generates the mechanical power, and whenthe fuel cell module reaches the predetermined temperature, the fuel gasobtained by reforming the hydrocarbon, together with the air or oxygen,is supplied to the fuel cell module, and the fuel cell module starts theelectric power generation and generates the electric power. When theelectric power generated by the fuel cell module is sufficient, theengine is stopped, and when the output generated by the fuel cell moduleis insufficient, the engine is started and the mechanical powergenerated by this engine is outputted.

Besides, as compared with the conventional fuel cell system usingmethanol as the raw material of the fuel gas supplied to the fuel cellmodule, which can not be supplied in a normal gasoline station, theinvention can use gasoline which can be supplied in a normal gasolinestation.

If the fuel cell module is made to be heated by the exhaust gasexhausted from the engine and can be started, since the fuel cell moduleis heated by the heat of the exhaust gas up to the temperature at whichthe fuel cell module can be started, the fuel cell module comes to becapable of generating electric power.

If the mechanical power generated by the engine is made to be convertedinto electric power by the generator and is outputted, when the engineis started, the generator is driven by the engine to generate theelectric power. As a result, when the electric power generated by thefuel cell module is sufficient, the engine is stopped, and when theelectric power generated by the fuel cell module is insufficient, theengine is started, and the mechanical power generated by the engine isconverted into electric power by the generator and is outputted.

If the electric power generated by one of or both of the fuel cellmodule and the generator is made to be stored in the secondary battery,when the output is insufficient, the electric power stored in thesecondary battery is outputted, and when the electric power generated bythe fuel cell module or the generator is superfluous, the electric powergenerated by the fuel cell module or the generator is stored in thesecondary battery.

If the electric power generated by one or at least two selected from thegroup consisting of the fuel cell module, the generator, and thesecondary battery is made to be outputted to the electric equipment, andthis electric equipment is driven by the electric power, when theelectric power outputted from the fuel cell module to the electricequipment is sufficient, the engine is stopped, and when the electricpower outputted to the electric equipment is insufficient, the engine isstarted, and the mechanical power outputted by the engine is convertedinto the electric power by the generator and is outputted to theelectric equipment.

If the fuel gas supplied to the electric power generating cell isreformed by the exhaust gas exhausted from the engine, the fuel gasbecomes the low hydrocarbon group most suitable for the electric powergenerating operation.

The fuel preheating pipe and the oxidant (air) preheating pipe areprovided in the fuel cell module, the oxidant (air) preheating pipe ispreheated by the exhaust gas exhausted from the engine, and the oxidantgas passing through the oxidant preheating pipe is heated. Further, thefuel preheating pipe is preheated by the exhaust gas exhausted from theengine, and the hydrocarbon containing water vapor passing through thefuel preheating pipe is reformed. Accordingly, when the fuel gas and theoxidant gas are supplied to the electric power generating cell, thewhole fuel cell module is quickly heated up to the most suitabletemperature and electric power generation is enabled.

If the reforming particles are filled in the fuel preheating pipe atsuch a density that hydrocarbon can flow, the fuel gas containing watervapor comes in contact with the reforming particles in the fuelpreheating pipe, and is reformed into the fuel gas of the lowhydrocarbon group, or the like and is supplied to the electric powergenerating cell.

If the exhaust gas of the engine is introduced into the reforming caseof the reformer and the reforming particles are filled in the reformingpipe contained in this reforming case, when hydrocarbon, together withwater, flows into the reforming pipe, this hydrocarbon and water areheated by the exhausted gas of the engine and are vaporized, and becomethe fuel gas containing water vapor. As a result, the fuel gascontaining the water vapor is efficiently reformed into the fuel gas ofthe low hydrocarbon group, or the like by the reformer.

Since the reformer is provided near the fuel cell module, the reformerabsorbs heat generated from the fuel cell module at the time of electricpower generation, and the fuel gas containing the water vapor is furtherefficiently reformed into the fuel gas of the low hydrocarbon group, orthe like, by the reforming particles in the reforming pipe.

If the reforming pipe in the reformer is heated by the first auxiliaryheater, since the hydrocarbon and water in the reforming pipe of thereformer is heated by not only the exhaust gas of the engine but alsothe first auxiliary heater, they are quickly vaporized into the fuel gascontaining the water vapor. Further, the fuel gas containing the watervapor comes in contact with the reforming particles in the reformingpipe, and is quickly reformed into the fuel gas of the low hydrocarbongroup, or the like.

If the fuel preheating pipe and the oxidant preheating pipe in the fuelcell module are heated by the second auxiliary heater, since the fuelgas and the oxidant gas are heated by not only the exhaust gas of theengine but also the second auxiliary heater, they are heated up to arelatively high temperature most suitable for electric power generation.Then, they are supplied to the electric power generating cell.

If the hydrocarbon having a high melting point, which is liquid at roomtemperature, among hydrocarbons is sprayed by the fuel injector and issupplied to the fuel preheating pipe, or water is sprayed by the waterinjector and is supplied to the fuel supply pipe, the liquid fuel orwater can be quickly vaporized.

Further, if the module temperature sensor for detecting the temperatureof the fuel cell module is inserted in the fuel cell module, and thecontroller controls the fuel cell module to start the electric powergenerating operation when the module temperature sensor detects that thefuel cell module is heated by the exhaust gas of the engine and reachesthe temperature at which electric power can be generated, the fuel cellmodule can efficiently generate electric power.

1. A hybrid power system comprising: a combustion engine for generatingmechanical power by combustion of a fuel gas mixture obtained byvaporizing hydrocarbon and air; a fuel cell module including: a cellcase having a first chamber and a second chamber divided by a partitionplate; and a fuel cell unit including a plurality of electric powergenerating cells for producing electricity at 930° C. or lower togenerate electric power, said fuel cell unit being located in said firstchamber, each of said electric power generating cells including: a fuelelectrode layer; an air electrode layer; and a solid electrolyte layerbetween said fuel electrode layer and said air electrode layer such thatsaid fuel electrode layer, said air electrode layer and said solidelectrolyte layer are laminated, said combustion engine and said fuelcell module being arranged such that at least one of the mechanicalpower generated by said combustion engine and the electric powergenerated by said fuel cell module is outputted; an exhaust gas supplypipe extending between said combustion engine and said cell case forintroducing exhaust gas from said combustion engine into said secondchamber of said cell case of said fuel cell module; a fuel preheatingpipe extending through said second chamber of said cell case of saidfuel cell module, said fuel preheating pipe being arranged to be heatedby the exhaust gas exhausted from said combustion engine and introducedinto said second chamber via said exhaust gas supply pipe so as topreheat fuel gas passing through said fuel preheating pipe so thathydrocarbon containing water vapor and passing through said fuelpreheating pipe is reformed; an oxidant preheating pipe extendingthrough said second chamber of said cell case of said fuel cell module,said oxidant preheating pipe being arranged to be heated by the exhaustgas exhausted from said combustion engine and introduced into saidsecond chamber via said exhaust gas supply pipe so as to preheat oxidantgas passing through said oxidant preheating pipe; wherein said fuelpreheating pipe is arranged to supply the preheated fuel gas obtained byreforming the hydrocarbon to said fuel electrode layer of each of saidelectric power generating cells, and said oxidant preheating pipe isarranged to supply the preheated oxidant gas to said air electrode layerof each of said electric power generating cells, so as to thereby heatsaid electric power generating cells to a predetermined temperature. 2.The hybrid power system of claim 1, wherein said combustion engine andsaid fuel cell module are arranged so that said fuel cell module isheated by the exhaust gas exhausted from said combustion engine.
 3. Thehybrid power system of claim 1, further comprising a generator forconverting the mechanical power generated by said combustion engine intoelectric power, and for outputting the electric power.
 4. The hybridpower system of claim 3, further comprising a secondary battery forstoring the electric power generated by at least one of a groupconsisting of said fuel cell module and said generator.
 5. The hybridpower system of claim 4, wherein the electric power from at least one ofa group consisting of said fuel cell module, said generator, and saidsecondary battery is outputted to electric equipment, and said electricequipment is driven by the outputted electric power.
 6. The hybrid powersystem of claim 5, wherein said electric equipment is an electric motor.7. The hybrid power system of claim 1, wherein said fuel preheating pipeincludes reforming particles filled therein at a density such that thehydrocarbon can flow therethrough.
 8. The hybrid power system of claim1, further comprising a first auxiliary heater for heating said fuelpreheating pipe.
 9. The hybrid power system of claim 8, furthercomprising a second auxiliary heater in said fuel cell module, saidsecond auxiliary heater being operable to heat said fuel preheating pipeand said oxidant preheating pipe.
 10. The hybrid power system of claim1, further comprising: a fuel supply pipe connected to a base end ofsaid fuel preheating pipe; and a fuel injector for spraying ahydrocarbon into said fuel supply pipe so as to supply the hydrocarboninto said fuel preheating pipe.
 11. The hybrid power system of claim 10,further comprising: a water supply pipe connected to said fuel supplypipe; and a water injector for spraying water into said water supplypipe so as to supply the water into said fuel supply pipe.
 12. Thehybrid power system of claim 1, further comprising: a reformer at saidcell case of said fuel cell module, said reformer including a reformingcase into which the exhaust gas of said combustion engine is introduced;and a reforming pipe housed in said reforming case and filled withreforming particles at a density such that the hydrocarbon can flowthrough said reforming pipe, said reforming pipe being connected to abase end of said fuel preheating pipe; wherein said reforming pipe isoperable to reform the hydrocarbon into one of a fuel gas of a lowhydrocarbon group or a fuel gas of CO or H₂, and is arranged to supplythe fuel gas to said electric power generating cells of said fuel cellmodule via said fuel preheating pipe.
 13. The hybrid power system ofclaim 12, further comprising a first auxiliary heater for heating saidfuel preheating pipe.
 14. The hybrid power system of claim 1, furthercomprising: a module temperature sensor inserted into said fuel cellmodule for detecting a temperature of said fuel cell module; and acontroller for controlling said fuel cell module to start generating theelectric power when said module temperature sensor detects that thetemperature of said fuel cell module has reached an electric powergeneration temperature for generating the electric power.
 15. The hybridpower system of claim 14, further comprising a secondary battery forstoring the electric power generated by at least one of a groupconsisting of said fuel cell module and a generator connected to saidcombustion engine, said controller being operable to control at leastone of a group consisting of said combustion engine, said fuel cellmodule, and said secondary battery based on a load of electric equipmentto be driven by the electric power.
 16. The hybrid power system of claim14, further comprising: a first auxiliary heater for heating said fuelpreheating pipe; a second auxiliary heater in said fuel cell module,said second auxiliary heater being operable to heat said fuel preheatingpipe and said oxidant preheating pipe; a fuel supply pipe connected to abase end of said fuel preheating pipe; a fuel injector for spraying ahydrocarbon into said fuel supply pipe so as to supply the hydrocarboninto said fuel preheating pipe; a water supply pipe connected to saidfuel supply pipe; a water injector for spraying water into said watersupply pipe so as to supply the water into said fuel supply pipe; areformer at said cell case of said fuel cell module, said reformerincluding a reforming case into which the exhaust gas of said combustionengine is introduced; an oxidant flow rate adjusting valve in an oxidantsupply pipe connected to a base end of said oxidant preheating pipe; anda reformer temperature sensor for detecting a temperature of saidreformer; wherein said controller is further operable to control saidfuel injector, said water injector, said oxidant flow rate adjustingvalve, said first auxiliary heater, and said second auxiliary heaterbased on respective detected temperature outputs of said moduletemperature sensor and said reformer temperature sensor.
 17. The hybridpower system of claim 14, further comprising: a communicating pipe forconnecting said first chamber of said cell case of said fuel cell moduleand said second chamber; a first motor valve in said communicating pipefor opening and closing said communicating pipe; an upstream sideexhaust pipe for connecting said combustion engine and said fuel cellmodule; a second motor valve in said upstream side exhaust pipe foropening and closing said upstream side exhaust pipe; an upstream sidebranch pipe for connecting said upstream side exhaust pipe and areformer; and a third motor valve in said upstream side branch foropening and closing said upstream side branch pipe; wherein saidcontroller is further operable to control said first motor valve, saidsecond motor valve, and said third motor valve based on respectivedetected temperature outputs of said module temperature sensor and areformer temperature sensor inserted in said reformer.
 18. The hybridpower system of claim 1, wherein the electric power from at least one ofa group consisting of said fuel cell module, a generator connected tosaid combustion engine, and a secondary battery is outputted to electricequipment, and said electric equipment is driven by the outputtedelectric power, and wherein an automobile, a ship, a train, an airplane,a motorcycle or construction equipment is driven by mechanical powergenerated by at least one of a group consisting of said electricequipment and said engine.